U.S. patent application number 10/671857 was filed with the patent office on 2005-03-31 for reclosable package having offset pull tab feature and related method of manufacture.
Invention is credited to Haws, Lewis Albert, McCracken, Kenny E..
Application Number | 20050069229 10/671857 |
Document ID | / |
Family ID | 34376206 |
Filed Date | 2005-03-31 |
United States Patent
Application |
20050069229 |
Kind Code |
A1 |
McCracken, Kenny E. ; et
al. |
March 31, 2005 |
Reclosable package having offset pull tab feature and related
method of manufacture
Abstract
A tamper-evident reclosable bag having a pull tab feature that
facilitates opening of a header by a consumer. The pull tab feature
is provided by an offset between the top and bottom webs (or front
and rear walls) of the package. One web has a cutout while the
other web has a portion that overlaps the cutout. The offset
provides a simple means for the consumer to grasp only one of the
webs of the package and then pull the webs apart or peel the offset
web away from the cutout web. The peeled-away layer can be provided
with a line of weakened tear resistance, allowing a section of the
header to, at the same time, be torn off the package. After the
tamper-evident seal provided by the header is broken, the consumer
can open the zipper, gaining access to the contents of the
package.
Inventors: |
McCracken, Kenny E.;
(Lawrenceville, GA) ; Haws, Lewis Albert; (Duluth,
GA) |
Correspondence
Address: |
OSTRAGER CHONG FLAHERTY & BROITMAN PC
250 PARK AVENUE, SUITE 825
NEW YORK
NY
10177
US
|
Family ID: |
34376206 |
Appl. No.: |
10/671857 |
Filed: |
September 25, 2003 |
Current U.S.
Class: |
383/61.2 ;
383/204; 383/64 |
Current CPC
Class: |
B65D 33/2591
20130101 |
Class at
Publication: |
383/061.2 ;
383/204; 383/064 |
International
Class: |
B65D 033/16 |
Claims
1. A reclosable package comprising: a receptacle comprising first
and second receptacle walls that oppose each other and an interior
space disposed between said first and second receptacle walls; a
flexible zipper comprising first and second zipper strips that are
mutually interlockable, said interior space being enclosed when
said zipper is closed; and a header that shrouds said zipper, said
header comprising first and second header walls joined to each
other in a first zone along a top of said header, and said first
header wall having a cutout in a corner of said header so that a
portion of said second header wall is offset relative to said first
header wall in said corner.
2. The reclosable package as recited in claim 1, further comprising
a slider mounted to said zipper, said slider being movable in a
first direction along said zipper for opening said zipper and
movable in a second direction along said zipper for closing said
zipper.
3. The reclosable package as recited in claim 1, wherein the ends
of said header are not sealed.
4. The reclosable package as recited in claim 1, wherein each of
said first and second zipper strips is flanged.
5. The reclosable package as recited in claim 1, wherein each of
said first and second zipper strips is flangeless.
6. The reclosable package as recited in claim 1, wherein said first
receptacle wall and said first header wall are respective portions
of a first sheet of film material, and said second receptacle wall
and said second header wall are respective portions of a second
sheet of film material.
7. The reclosable package as recited in claim 1, wherein said
second header wall has a line of weakened tear resistance that
extends laterally across at least a portion of the width of said
second header wall and at an elevation below interlocked profiles
of said first and second zipper strips.
8. The reclosable package as recited in claim 7, wherein said line
of weakened tear resistance comprises a multiplicity of spaced
perforations.
9. The reclosable package as recited in claim 7, wherein said line
of weakened tear resistance comprises a scoreline.
10. The reclosable package as recited in claim 7, wherein said line
of weakened tear resistance begins at one side of said second
header wall at an elevation below the lowest point of said cutout
in said first header wall.
11. The reclosable package as recited in claim 1, wherein one of
said first and second receptacle walls has a pocket formed therein,
further comprising a product residing in said pocket.
12. The reclosable package as recited in claim 11, wherein said
first and second receptacle walls are hermetically sealed to each
other along an entire periphery that surrounds said pocket.
13. A reclosable package comprising: first and second sheets of
film material sealed together on three sides to form a receptacle
having a mouth and an interior space and sealed across at least a
portion of a fourth side to form a header that shrouds said mouth;
and a flexible zipper shrouded by said header and comprising first
and second zipper strips that are mutually interlockable, said
first zipper strip being joined to said first sheet and said second
zipper strip being joined to said second sheet, said mouth of said
receptacle being closed when said zipper is closed, wherein said
first sheet has a cutout in a corner of said header so that a
portion of said second sheet in that corner is offset relative to
said first sheet.
14. The reclosable package as recited in claim 13, wherein said
second sheet has a line of weakened tear resistance that extends
laterally across at least a portion of the width of said second
sheet and at an elevation below interlocked profiles of said first
and second zipper strips.
15. The reclosable package as recited in claim 13, wherein one of
said first and second sheets has a pocket formed therein, further
comprising a product residing in said pocket.
16. The reclosable package as recited in claim 15, wherein said
first and second sheets are hermetically sealed to each other along
an entire periphery that surrounds said pocket.
17. A method of manufacture comprising the following steps: laying
out a bottom film having first and second mutually parallel edges;
forming a cutout in the bottom film adjacent the first edge;
placing a zipper closer to the first edge of the bottom film than
to the second edge but not overlapping the cutout, the zipper being
generally parallel to the first and second edges; joining the
zipper, as placed, to the bottom film; placing a top film over the
bottom film with the zipper therebetween, a portion of the top film
overlying the cutout; joining the top film to the zipper; and
joining the top film to the bottom film.
18. The method as recited in claim 17, wherein the cutout is formed
by cutting.
19. The method as recited in claim 17, wherein the cutout is formed
by punching.
20. The method as recited in claim 17, wherein the cutout is formed
by melting.
21. The method as recited in claim 17, further comprising the step
of cutting the top and bottom films and the zipper along two
parallel lines that run perpendicular to the zipper, one cut line
extending from the first edge to the second edge and the other cut
line extending from the cutout to the second edge.
22. The method as recited in claim 17, further comprising the step
of forming a line of weakened tear resistance in the top film, the
line of weakened tear resistance being parallel to the zipper.
23. The method as recited in claim 17, wherein the cutout is
triangular.
24. The method as recited in claim 17, wherein said joining steps
are performed by applying heat and pressure.
25. The method as recited in claim 17, further comprising the steps
of thermoforming a pocket in the bottom film and then placing
product in the pocket.
26. The method as recited in claim 25, wherein said step of joining
the top film to the bottom film comprises hermetically sealing the
top film to the bottom film along an entire periphery that
surrounds the pocket.
27. A method of manufacture comprising the following steps: forming
a cutout along a first edge of a web of film material having a
second edge parallel to the first edge; joining a zipper to the
web, the zipper not overlapping the cutout; and being generally
parallel to the first and second edges; making a reclosable package
that incorporates the joined zipper and web, the reclosable package
having a header that shrouds the zipper, with the cutout being
located in one corner of the header.
28. The method as recited in claim 27, wherein said package making
step comprises the following steps: folding the web so that the
first and second edges are generally aligned, with respective
portions of the web overlapping the cutout and the zipper; and
joining respective marginal portions of the folded web to form the
header.
29. The method as recited in claim 27, wherein said package making
step comprises the following steps: placing a second web over the
first web with the zipper between the webs, a portion of the second
web overlying the cutout; joining the second web to the zipper; and
joining the second web to the first web.
30. The method as recited in claim 29, further comprising the steps
of thermoforming a pocket in the first web and then placing product
in the pocket before the second web is placed over the first
web.
31. A reclosable package comprising: a receptacle comprising first
and second receptacle walls that oppose each other and an interior
space disposed between said first and second receptacle walls; a
flexible zipper comprising first and second zipper strips that are
mutually interlockable, said interior space being enclosed when
said zipper is closed; and a header that shrouds said zipper, said
header comprising first and second header walls joined to each
other in a first zone along a top of said header, and said first
header wall having a line of weakened tear resistance across a
corner of said header so that a corner portion of said first header
wall can be torn away from the remainder of said first header wall
when said corner of said header is pulled with sufficient
force.
32. The reclosable package as recited in claim 31, wherein said
line of weakened tear resistance comprises a multiplicity of spaced
perforations.
33. The reclosable package as recited in claim 31, wherein said
line of weakened tear resistance comprises a scoreline.
34. The reclosable package as recited in claim 31, wherein said
first header wall has another line of weakened tear resistance that
extends laterally across at least a portion of the width of said
first header wall and at an elevation below interlocked profiles of
said first and second zipper strips.
Description
BACKGROUND OF THE INVENTION
[0001] This invention generally relates to reclosable packaging. In
particular, the invention relates to reclosable bags having a
header that shrouds the zipper for providing a tamper-evident
feature.
[0002] In the use of plastic bags, pouches and other packages,
particularly for containing foodstuffs, it is important that the
bag be hermetically sealed and tamper evident until the purchaser
acquires the bag and its contents, takes them home, and opens the
bag or package for the first time. It is then commercially
attractive and useful for the consumer that the bag or package be
reclosable so that its contents may be protected. Such bags provide
the consumer with the ability to readily store, in a closed, if not
sealed, package any unused portion of the packaged product even
after the package is initially opened. Flexible plastic zippers
have proven to be excellent for reclosable bags, because they may
be manufactured with high-speed equipment and are reliable for
repeated reuse.
[0003] Many reclosable bags comprise a receptacle having a mouth
with a slider-actuated zipper installed therein for opening and
closing the bag. As the slider is moved in an opening direction,
the slider causes the zipper sections it passes over to open.
Conversely, as the slider is moved in a closing direction, the
slider causes the zipper sections it passes over to close.
Typically, a zipper for a reclosable bag includes a pair of
interlockable profiled closure strips that are joined at opposite
ends of the bag mouth. The profiles of interlockable plastic zipper
parts can take on various configurations, e.g. interlocking rib and
groove elements having so-called male and female profiles,
interlocking alternating hook-shaped closure elements, etc.
Reclosable bags having slider-operated zippers are generally more
desirable to consumers than bags having zippers without sliders
because the slider eliminates the need for the consumer to align
the interlockable zipper profiles before causing those profiles to
engage.
[0004] It is known to provide a zipper package construction that is
designed to undergo some permanent change in the package appearance
when the package is opened for the first time. In particular, it is
known to provide a zipper package with a header (sealed or open at
the ends) that extends over and shrouds the zipper, preventing
access to the slider. For example, the header may comprise
extensions of the front and rear package walls, the extensions
being joined at the top of the bag by a seal. The seal may be a
peel seal, which may be readily ruptured by a consumer to expose
the zipper and slider, or a "hard" seal, the latter being a seal
that is not intended to be broken. In the case of a header formed
using a hard seal, it is known to provide the package header with
one or more lines of perforations, which must be torn open by a
consumer to obtain access to the slider. In place of a line of
perforations (or to facilitate tearing the package along the line
of perforations), it is also known to provide one or more notches
at a side edge of the header for starting a tear across the header.
In any event, the header must be opened before access can be had to
the slider and zipper. If a package evidences a torn header before
the package is purchased by a consumer, this should indicate to the
consumer that the package has been tampered with, e.g., previously
opened.
[0005] Zipper package constructions with sealed headers should also
have other desirable features. For example, the package should be
"user friendly" in the sense that the steps necessary for the
initial opening of the package prior to the use of the zipper are
obvious or intuitive to the consumer. For certain tough plastics,
the header with dual tear lines may be difficult to tear off,
especially for persons with insufficient hand strength. Also the
zipper package design should allow the package to be formed on
conventional packaging equipment with little or no modification of
the equipment being required.
BRIEF DESCRIPTION OF THE INVENTION
[0006] The present invention is directed to a tamper-evident
reclosable bag having a pull tab feature that facilitates
separation of the joined webs (or walls) of a header by a consumer.
In one embodiment, the pull tab feature is provided by an offset
between the top and bottom webs (or front and rear walls) of the
package. One web has a cutout while the other web has a portion
that overlaps the cutout. The offset provides a simple means for
the consumer to grasp only one of the webs of the package and then
pull the webs apart or peel the offset web away from the cutout
web. After the header walls have been parted, the consumer can open
the zipper.
[0007] This invention may be applied to any style of reclosable
packaging having a header comprising opposing webs joined along the
top of the package. The package zipper may comprise either flanged
or flangeless zipper strips and may optionally be actuated by a
slider. Also the package may have thermoformed features, such as a
pocket in the receptacle area for product and/or a pocket in the
header area for a slider.
[0008] One aspect of the invention is a reclosable package
comprising: a receptacle comprising first and second receptacle
walls that oppose each other and an interior space disposed between
the first and second receptacle walls; a flexible zipper comprising
first and second zipper strips that are mutually interlockable, the
interior space being enclosed when the zipper is closed; and a
header that shrouds the zipper, the header comprising first and
second header walls joined to each other in a first zone along a
top of the header, and the first header wall having a cutout in a
corner of the header so that a portion of the second header wall is
offset relative to the first header wall in the corner.
[0009] Another aspect of the invention is a reclosable package
comprising: first and second sheets of film material sealed
together on three sides to form a receptacle having a mouth and an
interior space and sealed across at least a portion of a fourth
side to form a header that shrouds the mouth; and a flexible zipper
shrouded by said header and comprising first and second zipper
strips that are mutually interlockable, the first zipper strip
being joined to the first sheet and the second zipper strip being
joined to the second sheet, the mouth of the receptacle being
closed when the zipper is closed, wherein the first sheet has a
cutout in a corner of the header so that a portion of the second
sheet in that corner is offset relative to the first sheet.
[0010] A further aspect of the invention is a method of manufacture
comprising the following steps: laying out a bottom film having
first and second mutually parallel edges; forming a cutout in the
bottom film adjacent the first edge; placing a zipper closer to the
first edge of the bottom film than to the second edge but not
overlapping the cutout, the zipper being generally parallel to the
first and second edges; joining the zipper, as placed, to the
bottom film; placing a top film over the bottom film with the
zipper therebetween, a portion of the top film overlying the
cutout; joining the top film to the zipper; and joining the top
film to the bottom film.
[0011] Yet another aspect of the invention is a method of
manufacture comprising the following steps: forming a cutout along
a first edge of a web of film material having a second edge
parallel to the first edge; joining a zipper to the web, the zipper
not overlapping the cutout; and being generally parallel to the
first and second edges; making a reclosable package that
incorporates the joined zipper and web, the reclosable package
having a header overlying the zipper when the package is upright,
with the cutout being located in one corner of the header.
[0012] Other aspects of the invention are disclosed and claimed
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a drawing showing a front view of a reclosable
package in accordance with one embodiment of the invention.
[0014] FIG. 2 is a drawing showing a sectional view of the package
depicted in FIG. 1. The ovals represent heat seals.
[0015] FIG. 3 is a drawing showing a sectional view of a reclosable
package in accordance with another embodiment of the invention.
[0016] FIG. 4 is a drawing showing a sectional view of a reclosable
package in accordance with a further embodiment of the
invention.
[0017] FIG. 5 is a drawing showing a top view of one stage in the
manufacture of the reclosable package depicted in FIGS. 1 and
2.
[0018] FIG. 6 is a drawing showing a top view of a later stage in
the manufacture of the reclosable package depicted in FIGS. 1 and
2.
[0019] Reference will now be made to the drawings in which similar
elements in different drawings bear the same reference
numerals.
DETAILED DESCRIPTION OF THE INVENTION
[0020] FIG. 1 shows a top view of a thermoformed package 10
comprising a receptacle 2, a header 4 and a zipper 6 actuated by a
slider 8. The header 4 shrouds the zipper, while the zipper is
installed in the mouth of the receptacle. The receptacle 2 and the
header 4 may be formed by heating sealing top and bottom webs
(i.e., webs 14 and 16 seen in FIG. 2) of thermoplastic film
material together in a known manner. In this example, it has been
presumed that the top web is optically transparent, so that the
slider-actuated zipper is fully visible. The rectangle designated
by numeral 12 represents a pocket that has been thermoformed in the
bottom web. [The rectangle 12 is depicted using dashed lines to
reflect that the pocket lies under the top web.] In a typical
thermoforming packaging machine, each package-length section of a
bottom web is thermoformed to form a respective pocket before a
package-length section of zipper with a slider thereon is heat
sealed to the bottom web at a distance from the pocket.
[0021] The header 4 covers the zipper and acts as a tamper-evident
feature. The header may also be used to provide a means for hanging
the package on a hook on a display rack, e.g., by forming a hole in
the header and sliding the hole onto a hook on a display rack. The
package will then depend from the hook until removed by a
consumer.
[0022] Referring to FIG. 2, the zipper comprises a pair of
interlockable zipper strips 24 and 26 having respective flanges 28
and 30 extending from the closure profiles. [Only zipper strip 24
having a flange 28 is visible in FIG. 1, the other zipper strip
being directly behind.] Although FIG. 2 shows a rib and groove
arrangement, the closure profiles of the zipper strips may take any
form. For example, the zipper may comprise interlocking rib and
groove elements or alternating hook-shaped closure elements. The
zipper material may be made of polyethylene or other suitable
thermoplastic material.
[0023] As seen in FIG. 1, the zipper has slider end stops 18, 18'
and flange seals 20, 20' at respective ends thereof. The zipper
profiles are fused together at the end stops, while the zipper
flanges are fused together at the flange seals. The end stops 18,
18' perform dual functions, serving as stops to prevent the slider
from going off the end of the zipper and also holding the two
zipper profiles together to prevent the bag from opening in
response to stresses applied to the profiles through normal use of
the bag. The flange sealing provides resistance to package leakage
and also improves package strength by reinforcing the side welds.
The zipper assembly in the embodiment shown in FIG. 1 may have the
structure disclosed in detail in U.S. patent application Ser. No.
10/439,847, entitled "Method and Apparatus for Sealing Flanges and
Deforming Profiles of Plastic Zipper".
[0024] The slider for opening or closing the reclosable zipper is
generally shaped so that the slider straddles the zipper profiles.
The slider may be constructed with or without a separating finger
(also called a "plow"). The slider may be made in multiple parts
and welded together or the parts may be constructed to be snapped
together. The slider may also be of one-piece construction. The
slider can be made using any desired method, such as injection
molding. The slider can be molded from any suitable plastic, such
as nylon, polypropylene, polystyrene, acetal, polyketone,
polybutylene terephthalate, high-density polyethylene,
polycarbonate, or ABS.
[0025] As best seen in FIG. 2, the package is constructed by heat
sealing the top and bottom webs 14, 16 to each other and to the
zipper flanges 28, 30. The heat seals are indicated by ovals in
FIG. 2. The oval designated by numeral 32 represents a heat seal
joining marginal portions of the top and bottom webs at the peak of
the header; the oval designated by numeral 34 represents a heat
seal joining the top web 14 to the zipper flange 28; the oval
designated by numeral 36 represents a heat seal joining the bottom
web 16 to the zipper flange 30; and the ovals designated by 38a and
38b respectively represent two sides of a rectangular heat seal.
The four sides 38a through 38d of the rectangular heat seal are
shown in FIG. 6.) This rectangular heat seal is continuous and
joins the top and bottom webs along the entire perimeter of the
thermoformed pocket 12, thereby forming a hermetically sealed
receptacle for product. The ends of the header are not (but could
be) sealed.
[0026] Returning to FIG. 1, a pull tab feature in accordance with
one embodiment of the invention is formed by a cutout in one corner
of the bottom header wall. The cut line forms an edge 22, which
line is dashed to reflect that the cutout and edge 22 are part of
the bottom header, which lies under the top header wall in the view
given in FIG. 1 In this particular embodiment, the cutout is
represented as a triangle, but other shapes can be used, such as a
quarter circle, a trapezoid, or a rectangle. In each case, a
portion, i.e., "tab", 21 of the top header wall extends beyond the
edge 22 of the bottom header wall and overlies the cutout space.
The consumer can grasp the tab 21 between an index finger and
opposing thumb and then peel the top header wall away from the
bottom header wall. Peeling will start at the edge 22 of the bottom
header wall. Once separation of the top and bottom header walls has
been initiated, the consumer can then grasp more of the top header
wall and pull the grasped end of the top header wall across the
package toward the other end of the header. During this action, the
top header wall peels away from the bottom header wall along a
low-peel-strength header seal (item 68 in FIG. 6) and also tears
along a line of weakened tear resistance, i.e., tear line 72 (see
FIG. 1), formed in the top header wall. The tear line 72 runs
parallel to the zipper 6 at an elevation below the zipper profiles
and below the slider 8, so that the slider 8 is exposed when the
top header wall is torn off. However, the tear line could be higher
so that the slider is only partially exposed. The tear line should
be above the line of attachment of the zipper flange (item 28 in
FIG. 5) to the package so that the header wall is not also attached
to the package. The tear line 72 could be a line of spaced
perforations, a scoreline, a line of exposure to a weakening agent
(whether radiation or chemical), or equivalent means. Once a major
portion of the top header wall has been torn off, the consumer can
push the bottom header wall out of the way and proceed to
manipulate the slider to open the zipper.
[0027] Optionally, the bottom header wall is similarly provided
with a tear line running the length of the header. After the major
portion of the top header wall has been torn off, the consumer may
proceed to tear off a corresponding major portion of the bottom
header wall. The pull tab feature, in combination with tear lines,
enables the consumer to remove the top header wall first and then
the bottom header wall, instead of removing both at the same time.
Removing one header wall at a time is easier than removing both
sides of the header concurrently, especially for consumers with a
weak grasp.
[0028] FIGS. 5 and 6 depict two stages in the manufacture of the
package of FIG. 1. FIG. 5 shows a portion of an elongated
continuous bottom web 16 of film material, oriented in a horizontal
plane, that has been unwound from a supply reel and then advanced,
one package length per advance, through a pocket thermoforming
station, a zipper sealing station and a cutout station (which
stations are not shown in the drawings). The stage depicted in FIG.
5 occurs upstream of the position whereat the top web will be laid
on top of the bottom web. During each dwell time (between
advances), a large pocket or trough 12 for receiving a product and
a small pocket 66 for receiving part of a slider 8 are formed in
respective thermoforming dies (not shown) by application of heat
and vacuum; a triangular cutout 22 is formed at the cutout station,
e.g., by cutting along lines 22 and 23, which intersect at a vertex
of the triangle; and a package-length section of zipper carrying a
slider is sealed to the bottom web 16 along a portion laterally
offset from the pocket 12. The hatched band-shaped zone 58
represents the location where the flange of the lower zipper strip
is heat sealed to the bottom web 16. Bearing in mind that the
zipper is on its side during passage through the packaging machine,
item 28 in FIG. 5 represents the flange of the upper zipper strip.
Therefore, it should be appreciated that band 28 represents a
permanent heat seal between the flange of the bottom zipper strip
and the bottom web, with the flange of the top zipper strip
overlying the flange of the bottom zipper strip.
[0029] As a result of the foregoing V-shaped cut, a portion of the
bottom web in the shape of a right triangle is removed. This
operation is repeated once per package-length section of the bottom
web. For each cutting operation, the cut line 23 is generally
perpendicular to the adjacent edge of the bottom web and co-linear
with the dashed line 70, which extends in the cross direction and
represents where the cuts will be made to sever each completed
package from the continuous workpiece at a location downstream. In
contrast, the cut line 22 is inclined at an acute angle relative to
the cut line 23 and forms the hypotenuse of the triangle. As
previously noted, however, the shape of the cutout need not be
triangular. It could alternatively be a quarter circle, a
trapezoid, a rectangle, etc.
[0030] In accordance with the embodiment depicted in FIGS. 1 and 5,
only one end of the header on each package is provided with the
pull tab feature. Alternatively, both ends of the header could be
provided with pull tabs. In the latter event, then a portion of the
bottom web 16 would be cutout on both sides of the dashed line 70
in FIG. 5. This can be accomplished by making one cutout in the
shape of an equilateral triangle, each half of the equilateral
triangle being congruent to the right triangle seen in FIG. 5.
[0031] FIG. 6 shows a stage in the manufacturing process after
product (not shown) has been placed in the pocket 12 of the bottom
web and after a top web 14 has been unwound from a supply reel,
laid on top of the bottom web and heat sealed to the latter and to
the zipper. For the purpose of illustration, it is assumed that the
top web is made of optically transparent thermoplastic material, so
that the zipper and slider are visible in FIG. 6. The hatched
rectangular perimeter comprising sides respectively designated 38a
through 38d I FIG. 6 represents a continuous zone wherein the top
web 14 is heat sealed to the bottom web, thereby hermetically
sealing the pocket 12. Typically, the pocket is evacuated before
this hermetic seal is formed. Above the hermetic seal 38a-38d, the
hatched band-shaped zone 64 represents the location where the
flange of the upper zipper strip is heat sealed to the top web 14.
Typically, seal 64, shown in FIG. 6, would overlie seal 58, shown
in FIG. 5. Finally, the hatched band-shaped zone 68 adjacent one
edge of the top web represents the location where marginal portions
of the top and bottom webs are heat sealed to each other, thereby
forming a header that is open at both ends.
[0032] To avoid clutter in the drawing, FIG. 6 does not show the
line of weakened tear resistance (item 72 in FIG. 1) that is
provided in the top web 14 to facilitate tearing off the front
header wall, as previously described.
[0033] The broad scope of the invention further encompasses the
idea of substituting a line of weakened tear resistance (e.g., a
line of spaced perforations or a scoreline) for the cut 22. Instead
of a cutout, the result is that the corner of the header wall is
left attached to the rest of the header wall by means of material
along the line of weakened tear resistance. This material can be
easily torn away and remains attached to the other header wall as
the latter is being removed. In accordance with this embodiment, in
the low-peel-strength header seal 68 (see FIG. 6) extends to the
edge of the header, i.e., the front and rear header walls are
joined together in the corner.
[0034] The present invention can be incorporated in any reclosable
package having a header formed by opposing header walls that are
heat sealed together to form the apex of the header. Preferably,
the header heat seal has a peel strength that allows the respective
webs to be peeled apart in the manner disclosed herein. Two
examples of reclosable packages that may be provided with the pull
tab feature disclosed herein are depicted in FIGS. 3 and 4. Each of
these packages has a receptacle comprising a folded web that is
sealed at the sides, with the fold at the bottom.
[0035] FIG. 3 shows a reclosable bag wherein a web of film has been
folded and sealed at the sides to form a receptacle with opposing
walls 50 and 52 and a header 4. Opposing marginal portions of the
folded web are joined by a heat seal 32 (again represented by an
oval) to form the apex of the header. The reclosable bag further
comprises a zipper operated by a slider 8. The zipper comprises a
pair of interlockable zipper strips 24 and 26 having respective
flanges 28 and 30' extending from the closure profiles. The oval
designated by numeral 34 represents a permanent heat seal joining
the bag wall 50 to the zipper flange 28. The zipper flange 30',
which is longer than flange 28, is secured to bag wall 52 by
permanent heat seals 36 and 40. Flange 30' is also joined to bag
wall 50 by a permanent heat 46, which is located below the seal 34.
It should be appreciated that each of the seals 34, 36, 40 and 46
is a band of joined, e.g., fused, material that extends from one
side seal of the bag to the other side seal, thereby securing the
zipper to the bag along the width of the bag.
[0036] Zipper flange 18, which is longer than flange 32, is secured
to the bag front wall 10 by permanent seals 20 and 22 proximal to
the bag top. Flange 18 is further secured to the bag rear wall 10
by a permanent seal 28, which is located below the seal 34. It
should be appreciated that each of the seals 20, 22, 28 and 34 is a
band of joined, e.g., fused, material that extends from one side
seal of the bag to the other side seal, thereby securing the zipper
to the bag along the width of the bag. 8.
[0037] One or both of the corners (not shown in FIG. 3) of the
header 4 may have the pull tab feature of the present invention. In
this example, it is assumed that wall 50 has the offset while wall
52 has the cutout. Therefore, FIG. 3 shows that wall 50 is provided
with a line of weakened tear resistance 72 at an elevation below
the slider, to facilitate tearing off of a major portion of the
header wall that forms part of bag wall 50. After the header has
been breached in this manner, the consumer can move the slider to
open the zipper.
[0038] After the header is removed and the zipper is initially
opened by a consumer, the flange 30 still prevents access to the
package contents. The intact flange 30 provides hermetic sealing. A
line of weakened tear resistance is provided at the cusp 42 of the
flange 30. By bearing down on the flange 30 or pulling the zipper
strips apart, the line of weakness at cusp 42 can be ruptured,
thereby providing access to the contents. If the tear line
comprises perforations, the barrier posed by flange 30 can be
maintained prior to rupture by capping the line of perforations
with a frangible strip (not shown in FIG. 3) of lightweight
material, as disclosed in U.S. Pat. No. 5,023,122. This frangible
strip seals the perforations, but tears readily when the perforated
flange is ruptured along the perforations.
[0039] Another example of a reclosable bag with a header suitable
for incorporating the pull tab feature of the present invention is
shown in FIG. 4. In this embodiment, a web of film is folded into
the shape of an M; then a string zipper 6 is inserted between the
upper folds. The respective double layers of film on opposing sides
of the string zipper are heat sealed to the backs of the respective
flangeless zipper strips (not shown). Then a slider is inserted
onto the string zipper, with the sealed double layers disposed
between the respective backs of the zipper strips and the
respective side walls of the slider. The inner legs 50 and 52 of
the folded web form the opposing walls of the receptacle, while the
outer legs 54 and 56 are folded over the zipper and then their
edges are heat sealed to form the apex of a header. The heat seal,
which is indicated by oval 32, should have a low peel strength.
Again, such a construction lends itself to inclusion of the pull
tab feature of the present invention because the header walls can
be pulled apart. A tear line 72 can be provided on the header wall
that incorporates the pull tab.
[0040] Other embodiments will be apparent to persons skilled in the
art. In all embodiments, either header wall may have a pull tab,
while the other header wall has the cutout.
[0041] While the invention has been described with reference to
preferred embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for members thereof without departing from the scope of
the invention. In addition, many modifications may be made to adapt
a particular situation to the teachings of the invention without
departing from the essential scope thereof. Therefore it is
intended that the invention not be limited to the particular
embodiment disclosed as the best mode contemplated for carrying out
this invention, but that the invention will include all embodiments
falling within the scope of the appended claims.
[0042] As used in the claims, the verb "joined" means fused,
bonded, sealed, tacked, adhered, etc., whether by application of
heat and/or pressure, application of ultrasonic energy, application
of a layer of adhesive material or bonding agent, interposition of
an adhesive or bonding strip, etc. As used herein, the term
"cutout" means a space formed by removing a portion of a header
wall by any means, including but not limited to cutting, punching
or melting.
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